Military officials said Thursday substantial progress has been made in armoring United States military vehicles in Iraq — but given the increasing number and sophistication of those enemy roadside bombs, that is clearly not good enough.

It's a staggering new statistic. The Pentagon announced Thursday that 70 percent of American soldiers and Marines killed in Iraq today are victims of improvised explosive devices (IEDs).

At a House Armed Services committee hearing Thursday angry lawmakers were demanding to know why the Pentagon has not done more to protect U.S. forces in Iraq.

"And I come to this hearing with a sense of outrage,” said Rep. Curt Weldon, R-Pa. “I can’t tell you the number of homes I've sat in with soldier's families who've come home in body bags."

One major problem is the enemy keeps changing its tactics and its methods to detonate the bombs to defeat U.S. counter measures.

"We improvise better than the enemy improvises,” says Lt. Gen. James Mattis. “But it's a bloody issue and we have to keep improvising to stay ahead of it."

Thursday, at a plant in Cincinnati, the Armor Holding Company is turning out 550 fully-armored Humvees per month, and the Army says it will have more than 10,000 of those Humvees by July, right on target.

Of the nearly 2,700 Marine Corps Humvees in Iraq, fewer than 500 — that’s less than 18 percent — are fully armored, while the Marines have suffered some of the highest casualty rates, in some of the most intensive combat of the war.

In fact a Government Accountability Office report issued last month found that the Army failed to increase production of fully armored Humvees, in part because it didn’t have the enough money at hand to pay for it.

Some lawmakers today blame the Pentagon for not making fully armored Humvees a priority, sooner.

Lawmakers now say even more money must be spent on high-tech counter-measures, like electronic jammers, aimed at defeating those IEDs.